#include<iostream>
#include<iomanip>
using namespace std;

int main()           //计算平均年龄
{
    int n;
    cin >> n;
    double sum = 0;
    double average = 0;
    int age=0;
    for(int i=0;i<n;i++)
    {   
        cin >> age;
        sum = sum + age;
    }
    average = sum / n;
    cout << fixed << setprecision(2) << average << endl;
    return 0;
}